Localizing Noise Sources on a Rail Vehicle during Pass-By
This paper describes a pass-by measurement technique that has been developed for localization and visualization of noise sources on moving rail vehicles using beamforming. Based on measurements with an array of microphones, while also measuring the position of the vehicle, the technique calculates the contribution of noise, and visualizes it as a contour plot on top of a picture of the train. Deconvolution is applied in addition to traditional beamforming in order to get an improved spatial resolution in the noise map. A set of measurements was made on two different types of regional trains on the Danish railway: the Oresund trains and the IR4 trains. The speed of all the trains was approximately 120 km/h. The results show that deconvolution is efficient for identifying wind noise on the pantograph of the Oresund trains. The IR4 trains turned out to have a strong source at the very front part of the train for frequencies around 600 Hz - 800 Hz with a radiated sound power that was approximately 5 dB above the noise radiated by the noisiest bogies. The cause of this noise is yet unknown, but a potential explanation could be an aerodynamic phenomenon at the front.
Unable to display preview. Download preview PDF.
- 1.Michel, U., Barsikow, B., Helbig, J., Hellmig, M., Schüttpelz, M.: Flyover noise measurements on landing aircraft with a microphone array, AIAA Paper 98-2336Google Scholar
- 2.Hald, J., Ishii, Y., Ishii, T., Oinuma, H., Nagai, K., Yokokawa, Y., Yamamoto, K.: High-resolution fly-over beamforming using a small practical array. AIAA Paper (2012)Google Scholar
- 3.Sijtsma, P., Stoker, R.: Determination of absolute contributions of aircraft noise components using fly-over array measurements. AIAA Paper 2004-2958Google Scholar
- 5.Gomes, J.: Noise source identification with blade tracking on a wind turbine. In: Proceedings of Inter-Noise 2012, New York City (2012)Google Scholar
- 6.Lauterbach, A., Ehrenfried, K., Kröber, S., Ahlefeldt, T., Loose, S.: Microphone array measurements on high-speed trains in wind tunnels. In: Berlin Beamforming Conference, BeBeC (2010)Google Scholar
- 7.Le Courtois, F., Thomas, J.-H., Poisson, F., Pascal, J.-C.: Identification of the rail radiation using beamforming and a 2 D array. In: Proceedings of Acoustics 2012, Nantes (2012)Google Scholar
- 9.Ehrenfried, K., Koop, L.: A comparison of iterative deconvolution algorithms for the mapping of acoustic sources, AIAA Paper 2006-2711Google Scholar